- Charles Wilson
A term that is theoretically applicable to any mode or scale using eight different pitches to the octave, but which has found wide acceptance (since its adoption in Berger, 1963–4) as a designation for the scale (or pitch class collection) generated by alternating whole tones and semitones. A scalar order of the collection can begin with the semitone (the form termed ‘Model A’ by van den Toorn; e.g. C–C♯–D♯–E–F♯–G–A–A♯) or the tone (‘Model B’; e.g. C–D–D♯–F–F♯–G♯–A–B). Only three distinct transpositions are possible: the forms given above can be transposed to begin on C♯ and D, but any further transpositions will replicate one of those three forms in its pitch class content. The collection is therefore a ‘mode of limited transposition’ under Messiaen's definition (...